Browsing ant in the Northern Territory and Western Australia
Activities are still underway in the Northern Territory (NT) and Western Australia (WA) to eradicate infestations of browsing ant (Lepisiota frauenfeldi). Both of the state’s programs are on track to achieve eradication.
Browsing ants are not native to Australia and are a serious environmental pest. They can form super colonies that eat and displace native ant species, as well as other insects. The colonies can also damage plants and landscaping.
Current situation in WA
The first detection of browsing ant in WA was at Perth airport in 2013. This was followed by a detection at commercial properties in the suburb of Belmont in 2014. Browsing ants have now been eradicated from both sites with area freedom declared in 2016 and 2017 respectively.
Also in 2017, further browsing ant infestations were found at Welshpool and Kewdale, south-east of Perth. These infestations may be linked to the original infestation at Perth airport, possibly due to the movement of cargo between the airport and these areas.
In 2018, two browsing ants were detected at the RAAF base in Bullsbrook. Further surveillance over several months has failed to find further ants or a nest.
The Western Australian Department of Primary Industries and Regional Development (DPIRD) has treated all known infestations by spraying and using baits . For the Bullsbrook site, surveillance and treatment has been undertaken in association with the Australian Government Department of Agriculture and Water Resources and the Department of Defence.
During 2019, DPIRD will survey around 250 at-risk sites throughout WA. This work will be undertaken through an eradication response plan that was endorsed by the National Biosecurity Management Consultative Committee. That response plan will shortly be submitted to the National Biosecurity Management Group for final approval.
Current situation in the NT
Browsing ants were first detected in the NT in June 2015 at Darwin’s seaport. There are currently 20 infested premises in Darwin, the majority of which are located in the industrial suburb of East Arm, with a small number in nearby local areas.
Ongoing activities by the Northern Territory Department of Primary Industry and Resources have so far contained the ants. These activities involve tracing, surveillance, baiting, and spraying. They are funded by a nationally cost-shared eradication program approved by the National Biosecurity Management Group.
About browsing ants
Browsing ants are a slender ant, and are a consistent shiny dark brown in colour. They are 3–4mm in length with long antennae and long legs, and run about in a crazy or haphazard manner when disturbed.
They form super colonies, reaching large numbers and will be noticeable on the ground as well as in trees, leaf litter and infrastructure such as electrical boxes. They farm and protect scale insects which can eventually kill the plants they live on, and they eat and displace native ant species as well as other insects. The immediate impacts of browsing ant are considered to be environmental. However, the species’ ability to farm scale insects and the subsequent effects on plant health, indicates risk to agriculture and horticulture of national significance.
Browsing ants are commonly found in South East Asia including Timor Leste and Malaysia.
They form part of a group referred to as Tramp Ants.
What you need to do
It is important that people who live or work around the affected areas in the NT and WA are vigilant for these ants and report them if they see any suspect sightings.
Ants can hitchhike their way out of the area on goods and vehicles. In particular, they can be moved with shipping containers and cargo, as well as in soil, mulch, fertiliser and other plant material.
Before leaving any site where ants are present, check that they aren't in your consignment, and haven't crawled onto vehicles, equipment or clothing.
The movement restrictions mandated at infested sites must be adhered to so these ants are not inadvertently moved out of the area or interstate.
If you think you've found a browsing ant population, you must report it to the Exotic Plant Pest Hotline on 1800 084 881 as soon as possible.